Hall-sensor component

ABSTRACT

The invention relates to a Hall-sensor component ( 1 ), comprising a Hall sensor ( 2 ) that is traversed by an electric current and a processing device ( 2 ) for processing an input signal. A Hall signal, which is dependent on a magnetic field that acts on the Hall sensor ( 2 ) and the electric current is emitted by the Hall sensor ( 2 ). The processing device ( 3 ) is connected downstream of the Hall sensor ( 2 ), said device emitting an output signal that is assigned to the input signal. The Hall sensor ( 2 ) and the processing device ( 3 ) form a subassembly, to which a diagnostic signal generated by a signal generator ( 4 ) is supplied. The Hall signal is linked directly or indirectly to the diagnostic signal, whereby the Hall signal linked to said diagnostic signal is supplied to the processing device ( 3 ) as the input signal.

[0001] The present invention pertains to a Hall sensor component withthe features according to the preamble of patent claim 1.

[0002] Hall sensors have been known from the prior art. They comprise,in principle, a conductive sensor surface, through which a currentflows. If a magnetic field interacts with the sensor surface throughwhich the current flows, the charged particles generated by the currentare deflected on the basis of the Lorentz force, as a result of which anelectric field is generated in the sensor surface, which is the causefor a voltage being present at lateral edges of the sensor surface. Thisvoltage, which is called the Hall voltage, is proportional to theproduct of the magnetic flux density of the magnetic field and thecurrent flowing through the sensor surface, so that the magnetic fluxdensity can be determined by measuring the Hall voltage at a knowncurrent except for a proportionality factor, which depends, among otherthings, on the geometric dimensions of the sensor surface.

[0003] Hall sensors are available commercially, e.g., in the form ofHall sensor components, in which a processing device, which processesthe Hall signal sent by the Hall sensor for an evaluation and sends asignal associated with the Hall signal as an output signal, is arrangeddownstream of the Hall sensor proper. Both the Hall sensor and theprocessing device are integrated in a single housing.

[0004] Hall sensor components are equipped with different processingdevices for different possible applications. One possible applicationis, e.g., the determination of the magnetic flux density of the magneticfield acting on the Hall sensor by means of the Hall sensor component.The processing device is preferably designed for this purpose such thatthere is a linear dependence between the signal intensity of the outputsignal and the magnetic flux density in the broadest possible range.

[0005] Another possible application is the use of a Hall sensorcomponent in conjunction with a magnet as a switching device subject tolittle friction loss, which can be switched into at least two switchingstates with a switch lever. A magnet, which is brought into the range ofaction of a Hall sensor component associated with the first switchingstate in a first switching state of the two switching states, isprovided at the switch lever. The range of action is defined here as thearea in space around the Hall sensor component, into which the magnetmust be brought in order to bring about such an increase in the value ofthe Hall sensor that a first threshold value preset by the processingdevice will be exceeded. By setting this threshold value, it is thuspossible to set the distance in space between the magnet and the Hallsensor provided in the Hall sensor component, below which distance theactual distance is to drop and at which the first switching state isconsidered to be switched on. Furthermore, a second threshold value, bywhich the distance in space between the magnet and the Hall sensor,which is to be exceeded and at which the first switching state isconsidered to be switched off, is preset by the processing device. Thesecond threshold value may differ from the first threshold value, sothat a so-called switching hysteresis is provided by the processingdevice. The processing device may be equipped, e.g., with a Schmitttrigger as a threshold value transducer to embody this switchinghysteresis. The Hall sensor component may, of course, also be arrangedat the switch lever in such low-friction switching devices. The Hallsensor component can be introduced in this case into the magnetic fieldof the magnet by moving the switch lever.

[0006] However, the more circuits are arranged downstream of the Hallsensor proper in the Hall sensor component, the greater is also the riskfor failure of the Hall sensor component because of a defect in one ofthese circuits. If a prior-art Hall sensor component fails because ofsuch a defect, the problem frequently arises that the ability of theHall sensor component to function cannot be checked in the installedstate or during operation, so that the defect is not recognized.

[0007] The basic object of the present invention is to provide a Hallsensor component in which the possibility of checking its ability tofunction is improved.

[0008] This object is accomplished according to the present inventionwith a Hall sensor component with the features according to patentclaim 1. Preferred variants are described in the subclaims.

[0009] The Hall sensor component according to the present invention hasa Hall sensor, through which an electric current flows, and a processingdevice for processing an input signal. The Hall sensor sends a Hallsignal, which depends on a magnetic field acting on the Hall sensor andon the electric current. A processing device, which sends an outputsignal that is associated with and depends on the input signal, isarranged downstream of the Hall sensor. The Hall sensor and theprocessing device form one assembly unit, to which a diagnosis signalgenerated by a signal generator is sent. The Hall sensor is linkedindirectly or directly with the diagnosis signal, and the Hall signallinked with the diagnosis signal is sent to the processing device as aninput signal.

[0010] Since the Hall signal which is directly or indirectly linked withthe diagnosis signal is sent according to the present invention to theprocessing device, the output signal is also affected by the diagnosissignal in a characteristic manner. However, two signal components, ofwhich a first signal component characterizes the magnetic field and thesecond signal component characterizes the diagnosis signal, are thusderived according to the present invention from the output signal, thefirst signal component of the output signal being hereinafter called themagnetic component and the second signal component of the output signalbeing called the diagnosis component.

[0011] The diagnosis signal used may be any signal insofar as thediagnosis component and the magnetic component can be derived from theoutput signal. However, the diagnosis signal is preferably a periodicsquare wave signal.

[0012] The diagnosis signal can be sent to the Hall sensor in differentways. According to a first alternative, the Hall sensor may be directlylinked with the diagnosis signal. The direct linking of the Hall signaland the diagnosis signal takes place only at or behind the output of theHall sensor and may be embodied, e.g., by adding the Hall signal and thediagnosis signal by means of an analog adder to form a mixed signal,which will then form the input signal of the processing device.

[0013] However, according to a second alternative, the Hall signal mayalso be linked indirectly with the diagnosis signal by the electriccurrent flowing through the Hall sensor being controlled as a functionof the diagnosis signal.

[0014] If a periodic square wave signal, which alternatingly assumes alogic H level and a logic L level as a signal state, is sent to the Hallsensor in the case of the indirect linking of the Hall signal and thediagnosis signal, the current flowing through the Hall sensor ispreferably switched on and off as a function of the signal state of thesquare wave signal. This means that the current is switched on when thesquare wave signal has a logic H level, and the current is switched offwhen the square wave signal has a logic L level or vice versa. Thecurrent flowing through the Hall sensor may be supplied by the signalgenerator.

[0015] The signal generator may be arranged outside the Hall sensorcomponent, in which case the diagnosis signal is sent via a connectionprovided at the Hall sensor component. However, the signal generator ispreferably integrated within the Hall sensor component.

[0016] If the processing device has a switching hysteresis with twothreshold values regarding its input, and if the diagnosis signal is aperiodic signal, the frequency of the diagnosis signal is preferablychanged as a function of the Hall signal. In this case, the diagnosissignal linked with the Hall signal has a sufficiently high level atleast once within one period to exceed a first of the threshold valuesand a sufficiently low level at least once to drop below the secondthreshold value. The signal generator is designed now as avoltage-controlled oscillator (VCO), which changes the frequency of thediagnosis signal as a function of the value of the Hall voltage.

[0017] Furthermore, an evaluating device, by which the diagnosiscomponent is recognized as such and evaluated, may be arrangeddownstream of the processing device. Based on this evaluation, it willthen be recognized whether the Hall sensor component is operatingcorrectly at least with respect to the processing device.

[0018] The Hall sensor component according to the present inventionforms a diagnosable component, which is preferably used where therecognition of the failure of the sensor would be desirable for safetyreasons to prevent damage to humans or equipment.

[0019] A possible field of use of the Hall sensor component according tothe present invention is, e.g., the area of motor vehicle electronics,especially the shifting of gears, for which Hall sensor components areused to form a low-friction shifting device.

[0020] To recognize the current shifting state of the gearshift lever inthe passenger compartment, a magnet, which enters the range of action ofone of the associated Hall sensor components in a certain shiftposition, may be arranged, e.g., at the gearshift lever of the gearshift mechanism in such a shifting device. This Hall sensor component ispreferably formed by the Hall sensor component according to the presentinvention, so that a failure of this component can be recognized by acontrol electronic unit arranged in the motor vehicle. It is thuspossible to check the ability of the Hall sensor component used in thegear shift mechanism to function by means of the control electronic unitarranged in the motor vehicle. If the failure of the Hall sensorcomponent or of one of the Hall sensor components used in the gear shiftmechanism is recognized, it is possible to display this failure to thedriver and/or to allow a safety program associated with the failure torun in order to prevent a possible incorrect shifting of thetransmission and consequently a possible damage to the driver or thevehicle. The Hall sensor component may, of course, be arranged at thegearshift lever in this case as well. The Hall sensor component can bebrought in this case into the magnetic field of the magnet by themovement of the gearshift lever.

[0021] The present invention will be described on the basis of preferredembodiments with reference to the drawings. In the drawings,

[0022]FIG. 1 shows a block diagram of a Hall sensor component accordingto the present invention according to a first embodiment of the presentinvention,

[0023]FIG. 2 shows a schematic view of the Hall sensor and of the signalgenerator according to the first embodiment, and

[0024]FIG. 3 shows a block diagram of a Hall sensor component accordingto the present invention according to a second embodiment of the presentinvention.

[0025]FIGS. 1 and 2 show a block diagram and a schematic view,respectively, of a Hall sensor component according to the presentinvention according to a first embodiment of the present invention. TheHall sensor component 1 has a Hall sensor 2 and a processing device 3,which are integrated in a housing, not shown. A signal generator 4,which is likewise integrated in the housing, generates a current I,which flows through the Hall sensor 2. The Hall sensor 2 is exposed to amagnetic field, which is the cause for a Hall voltage, which is sent bythe Hall sensor 2 and is proportional to the product of the current Iand the magnetic flux density B of the magnetic field. The curvedescribing the current I generated by the signal generator 4 over timecorresponds to a periodic square wave signal, whose characteristic shapeis also reflected by the signal U_(M) sent by the Hall sensor. A dualfunction is assigned to the current I here. On the one hand, the currentI is used to operate the Hall sensor 2 and, on the other hand, it isused as a diagnosis signal based on its periodic characteristic.Consequently, the signal U_(M) is a mixed signal, and the value of themagnetic flux density B is reflected by the amplitude of the mixedsignal, and the frequency of the current I is reflected by the periodiccomponent of this mixed signal. The mixed signal U_(M) consequently hasa diagnosis signal component and a Hall voltage component.

[0026] The mixed signal U_(M) is sent to the processing device 3, whichsends as an output signal a signal U_(A), which is associated with anddepends on the mixed signal U_(M) and which likewise has a diagnosissignal component (diagnosis component) and a Hall voltage component(magnetic component).

[0027] The diagnosis component of the output signal U_(A) is recognizedand evaluated by an evaluating device, which is not shown and isarranged downstream of the processing device 3, so that it can bedetermined based on the evaluation whether the Hall sensor component isoperating correctly at least with respect to the processing device.

[0028]FIG. 3 shows a block diagram of a Hall sensor component accordingto the present invention according to a second embodiment of the presentinvention, where the reference numbers used for the features accordingto the second embodiment are identical to the reference numbers used forthe same or similar features according to the first embodiment.

[0029] The second embodiment is essentially identical to the firstembodiment except for the integration of the signal generator 4 in theHall sensor component. According to the second embodiment, the signalgenerator 4 is arranged, namely, outside the Hall sensor component, andthe diagnosis signal generated by the signal generator is sent as anexternal diagnosis signal to the assembly unit formed by the Hall sensor2 and the processing device 3. List of Reference Numbers: 1 Hall sensorcomponent 2 Hall sensor 3 Processing device 4 Signal generator

1. Hall sensor component with a said Hall sensor (2), through which anelectric current flows and which sends a Hall signal, which depends on amagnetic field acting on the said Hall sensor (2) and the electriccurrent, and a said processing device (3) arranged downstream of thesaid Hall sensor (2) for processing an input signal, which sends anoutput signal associated with the input signal, characterized in that adiagnosis signal generated by a signal generator is sent to the saidassembly unit (2, 3) formed by the said Hall sensor (2) and the saidprocessing device (3), wherein the Hall signal is indirectly or directlylinked with the diagnosis signal, and the Hall signal linked with thediagnosis signal is sent as an input signal to the said processingdevice (3).
 2. Hall sensor component in accordance with claim 1,characterized in that the Hall signal sent by the said Hall sensor (2)is directly linked with the diagnosis signal.
 3. Hall sensor componentin accordance with claim 2, characterized in that the Hall signal issuperimposed to the diagnosis signal by means of an analog adder. 4.Hall sensor component in accordance with claim 1, characterized in thatthe Hall signal is indirectly linked with the diagnosis signal by theelectric current flowing through the Hall sensor being controlled as afunction of the diagnosis signal.
 5. Hall sensor component in accordancewith one of the claims 1 through 4, characterized in that the diagnosissignal is a periodic square wave signal, which alternatingly assumes alogic H level and a logic L level.
 6. Hall sensor component inaccordance with claims 4 and 5, characterized in that the electriccurrent is switched on at a logic H level of the square wave signal andis switched off at a logic L level of the square wave signal.
 7. Hallsensor component in accordance with one of the claims 1 through 6,characterized in that the said signal generator (4) is integrated withinthe Hall sensor component.